as in treacherous
formal
causing harm in a way that is gradual or not easily noticed
Most people with this insidious disease have no idea that they are infected. an insidious enemy
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Example Sentences
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Recent Examples of insidious
Political discussions on social media are often dominated by competing attributions of more and more insidious motives to people on the other side.
—
Mark Schroeder, The Conversation, 20 Feb. 2026
Here, the joyous and the boisterous contrast the dark and insidious, allowing viewers to both be delighted by colorful street scenes and celebrations while the rot of fear creeps in, as the details surrounding our main character (Wagner Moura) and his predicament are revealed.
—Megan Spurrell, Condé Nast Traveler, 11 Feb. 2026
The abstracting reached its pinnacle (nadir) with an insidious Alexa ad featuring Chris Hemsworth and wife Elsa Pataky.
—Steven Zeitchik, HollywoodReporter, 9 Feb. 2026
The takeover of the arts is less violent and a bit more insidious, but just as dangerous in its own right.
—Voice Of The People, New York Daily News, 8 Feb. 2026
See All Example Sentences for insidious
Mark Schroeder, The Conversation, 20 Feb. 2026
Here, the joyous and the boisterous contrast the dark and insidious, allowing viewers to both be delighted by colorful street scenes and celebrations while the rot of fear creeps in, as the details surrounding our main character (Wagner Moura) and his predicament are revealed.
—Megan Spurrell, Condé Nast Traveler, 11 Feb. 2026
The abstracting reached its pinnacle (nadir) with an insidious Alexa ad featuring Chris Hemsworth and wife Elsa Pataky.
—Steven Zeitchik, HollywoodReporter, 9 Feb. 2026
The takeover of the arts is less violent and a bit more insidious, but just as dangerous in its own right.
—Voice Of The People, New York Daily News, 8 Feb. 2026
See All Example Sentences for insidious
Recent Examples of Synonyms for insidious
Adjective
-
The corridor has major safety issues, such as speeding and treacherous turns out of strip malls.—
Carolyn Gusoff,
CBS News,
6 Mar. 2026
-
The sport has only grown since then, with paths to championships proving more treacherous than ever before.—
Jace Frederick,
Twin Cities,
2 Mar. 2026
Adjective
-
The subtle split among Democrats began emerging minutes after the first US strikes on Saturday.—
Nicholas Wu,
semafor.com,
5 Mar. 2026
-
This Madewell pair is made from high-quality denim with a subtle stretch to hug your curves and ensure all-day comfort.—
Jordan Julian,
InStyle,
5 Mar. 2026
Adjective
-
Richards and the governor’s office pushed back on false assertions that Newsom and his wife, First Partner Jennifer Siebel Newsom, were stealing money from the state through her office that same day.—
Taryn Luna,
Los Angeles Times,
6 Mar. 2026
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Air power cannot overthrow a government, some say, which is on one level true—a fighter jet cannot take the keys to the presidential palace, after all—and on another level, obviously false.—
Eliot A. Cohen,
The Atlantic,
6 Mar. 2026
Adjective
-
Then again, averages can be deceptive.—
Burkhard Bilger,
New Yorker,
2 Mar. 2026
-
The recovered funds come from 89 separate settlements and other restitution paid back by doctors, nurses and health care systems after fraud investigations related to deceptive billing practices, pill and medication theft, and other fraud.—
Hayleigh Colombo,
IndyStar,
27 Feb. 2026
Adjective
-
Observing human behavior confirms that for some among us, the perfidious lust for unbridled power and the imposition of cruelty in its quest know no bounds and are bereft of human decency.—
A.O. Scott,
New York Times,
3 Feb. 2026
-
However, this question has now been resurrected and amplified by conservatives as evidence of a perfidious lack of patriotism.—
Charlie Campbell,
Time,
2 Feb. 2026
Adjective
-
And the claim of widespread abuse of sheep during shearing is incorrect.—
U T Readers,
San Diego Union-Tribune,
3 Mar. 2026
-
More than 14,000 child car seats were recalled by the National Highway Traffic Safety Administration (NHTSA) after officials said incorrect information was included in the seats' safety manuals.—
Fernando Cervantes Jr,
USA Today,
3 Mar. 2026
Adjective
-
The helpful staff won’t steer you wrong.—
Condé Nast,
Condé Nast Traveler,
7 Mar. 2026
-
An officer monitoring a vehicle X-ray machine did not detect anything wrong with the vehicle, but another officer doing a physical inspection spotted the woman’s foot, according to the complaint.—
Alex Riggins,
San Diego Union-Tribune,
7 Mar. 2026
Cite this Entry
“Insidious.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/insidious. Accessed 11 Mar. 2026.
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